serializing data and tables while reinstantiating Lua. That's
ugly, and can't serialize some things (eg. functions).
Instead, when changing themes, shut down the high-level objects
and unregister as much as we can from Lua, change the theme,
then reregister things. This doesn't clean the slate as much;
globals won't be erased, etc.
A better way would be to clear everything that uses Lua
(delete singletons), then reload it all. Singleton creation is
a bit of a mess currently so that would break a lot, and we
don't want to reload songs.
Glenn Maynard